Compounds containing a pentabromobenzyl moiety are known to be flame retardants. Pentabromobenzyl acrylate (EP 481126), pentabromobenzyl terephthalate (DE 33 20 333), and pentabromobenzyl tetrabromophthalate (EP 47866) are reported to be used in flame retardant polymer compositions. All the above mentioned compounds are esters of carboxylic acids. It is generally known that the ester group is rather unstable to hydrolysis, especially in the presence of acids and bases. This hydrolytic decomposition of esters precludes their use in a great number of applications.
While it is generally recognized that compositions containing bromine improve the flame retardancy of polymers, many bromine-containing compounds are unsatisfactory due to their instability. Such compounds are known to undergo dehydrobromination when incorporated in polymers.
Therefore there is a demand for fire retardants retaining their stability against hydrolysis, especially in the presence of acids and bases. In addition, there is a demand for bromine-containing fire retardants having stability against dehydrobromination when incorporated in polymers.
It is an object of present invention to provide a bromine-containing fire retardant, which has excellent fire-retardancy properties.
It is another object of present invention to provide such fire retardant retaining its stability against hydrolysis and/or decomposition in the presence of an acid or a base.
It is yet a further object of present invention to provide such fire retardant eliminating the undesired dehydrobromination process when incorporated in polymers.
It is yet a further object of present invention to provide fire retarded polymeric and polymer-containing compositions comprising such bromine-containing fire retardant.
The present invention provides novel pentabromobenzyl alkyl ethers possessing highly satisfactory flame retarding characteristics (properties) while retaining their stability against undesired processes, such as dehydrobromination and hydrolysis. The invention further provides polymeric and polymer-containing compositions containing the said novel pentabromobenzyl alkyl ethers that exhibit excellent fire retardancy.
Other objects and advantages of the invention will become apparent as the description proceeds.